Graft copolymer, composition containing the same and molded object thereof, and process for producing the same

ABSTRACT

A graft copolymer having a structure in which a vinyl copolymer segment formed from a vinyl monomer having an acid is suspended in a molecular chain of a polyolefin resin segment via a β-substituted propylene group is obtained, by reaction of polyolefin resin having β-substituted propenyl group as a pendant and a vinyl monomer having an acid, and further a graft copolymer composition containing the same and a molded product thereof are obtained. The obtained graft copolymer, the composition containing the same and the molded product thereof are excellent in adhesive property to a polar material and scratch resistance.

TECHNICAL FIELD

The present invention relates to a graft copolymer excellent in adhesionto a polar material and scratch resistance, a composition containing thesame and a molded product thereof, and a method for producing the graftcopolymer.

BACKGROUND ART

Among thermoplastic resins, polyolefin resin enables light weight andgood cost efficiency and is excellent in moldability, chemicalresistance, and mechanical strength, and thus it is used for variousapplications as film, fiber, and molding material.

However, since polyolefin resin has low polarity and smallintermolecular force, it has problems in that coating property, adhesiveproperty to and compatibility with polar material, and scratchresistance are inferior.

To solve these problems, a lot of copolymer compositions in which avinyl monomer having an acid is generally grafted are proposed.

For example, to improve adhesive property of polyolefin resin, a graftcopolymer in which a vinyl polymer segment formed from a vinyl monomerhaving carboxylic acid is directly bonded to polypropylene resin segmentis proposed (see Patent Document 1: Japanese Patent No. 2885919, page 2to 3).

Further, to improve adhesive property and scratch resistance ofthermoplastic elastomer, proposed is a method of blending a graftcopolymer with thermoplastic elastomer, the graft copolymer in which avinyl polymer segment formed from a vinyl monomer having carboxylic acidis directly bonded to ethylene•α-olefin copolymerized rubber segment(see Patent Document 2: Japanese Patent Publication No. 2-51455 (page3)).

However, in the graft copolymer disclosed in Patent Documents 1 and 2,since the vinyl copolymer segment formed from a vinyl monomer havingcarboxylic acid is directly bonded to polypropylene resin orethylene•α-olefin copolymerized rubber, the improvement effects onadhesive property and scratch resistance are not sufficient and furtherimprovements have been expected.

Furthermore, the graft copolymers disclosed in these documents areproduced by a method in which the vinyl monomer is directly reactedthrough grafting with the polyolefin resin using a polymerizationinitiator, and thus they have some problems in that the reactivityduring graft reaction is low and side reaction such as disintegration orcrosslinking of polyolefin resin occurs during the reaction. It is thusconsidered that a graft copolymer having excellent properties is hard tobe obtained by these methods.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a graft copolymerexcellent in adhesive property to a polar material and scratchresistance, a composition containing the same and a molded productthereof, and a method for producing the graft copolymer.

To achieve the above object, the graft copolymer of the presentinvention has a structure in which a vinyl copolymer segment formed froma vinyl monomer having an acid is suspended via β-substituted propylenegroup in a molecular chain of a polyolefin resin segment.

The present invention further provides a graft copolymer resincomposition containing the graft copolymer and a molded product thereof.

The present invention furthermore provides a method for producing thegraft copolymer. In that method, a vinyl monomer having an acid isreacted with polyolefin resin having a β-substituted propenyl group as apendant.

BEST MODE FOR CARRYING OUT THE INVENTION

A graft copolymer of the present invention having a structure in which avinyl polymer segment formed from a vinyl monomer having an acid issuspended from a polyolefin resin segment via a β-substituted propylenegroup, preferably a β-substituted propylene group of the chemicalformula (A).

In the formula (A), R¹ represents a phenyl group, a cyano group, or analkylester group (—COOR^(m), wherein R^(m) represents an alkyl grouphaving 1 to 4 carbon atoms).

Examples of the above β-substituted propylene group include a2-phenyl-1,3-propylene group, a 2-cyano-1,3-propylene group, and a2-acetoxy-1,3-propylene group. Among them, 2-phenyl-1,3-propylene groupis preferable.

The amount of β-substituted propylene group contained in the graftcopolymer is, for example, calculated from the amount of methine groupbonded to β-substituted group, obtained from ¹H-NMR of the graftcopolymer. The preferable amount of β-substituted propylene group is 0.1to 15% by weight in the graft copolymer. When the amount of theβ-substituted propylene group is less than 0.1% by weight in the graftcopolymer, the performances of the graft copolymer such as adhesiveproperties and scratch resistance are relatively low, and it isunfavorable. Further, when the amount of the β-substituted propylenegroup in the graft copolymer exceeds 15% by weight, the desirableproperties of polyolefin resin cannot be obtained.

The polyolefin resin segment constituting the graft copolymer is ahomopolymer of α-olefins having two or more carbon atoms, such asethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and1-octene (hereinafter abbreviated as α-olefins), a copolymer of two ormore α-olefins, a copolymer of α-olefin and other vinyl monomer, or amixture thereof.

Among them, polyethylene resins, polypropylene resins, or olefinelastomers are preferable from an economical viewpoint, and inparticular, olefin elastomers synthesized with a metallocene catalyst ismore preferable.

Hereafter, each resin will be described in detailed.

As the polyethylene resin, a homopolymer of polyethylene, a copolymercontaining 80 or more % by mol of polyethylene, or a mixture thereof canbe used.

Specific examples thereof include a low density polyethylene, a linearlow density polyethylene, and a high density polyethylene.

In addition, the polyethylene resins usually having a melt flow rate of0.01 to 100 g/10 min. (JIS K 7210: 190° C., 2.16 kg of load) and adensity of 0.88 to 0.98 g/cm³ (ASTM D 1505) are preferable from aviewpoint of the production.

As the polypropylene resin, a homopolymer of polypropylene, a copolymercontaining 80 or more % by mol of polypropylene, or a mixture thereofcan be used. Among them, a random or block copolymer ofpropylene-ethylene containing 1 to 10% by weight of ethylene ispreferable. In addition, the polypropylene resins usually having a meltflow rate of 0.01 to 100 g/10 min. (JIS K 7210: 230° C., 2.16 kg ofload) are preferable from a viewpoint of the production.

As the olefin elastomer, usable are a copolymer rubber of 2 or morekinds of α-olefin, or a copolymer of α-olefin and vinyl monomer, and amixture or partially crosslinking substance thereof, and further anolefin thermoplastic elastomer, that is a mixture of these products, anda polyethylene resins or a crystalline polyolefin resin such ascrystalline polyolefin resin.

Specific examples thereof include: ethylene-α-olefin copolymer rubberssuch as ethylene-propylene copolymer rubber, ethylene-butene copolymerrubber, ethylene-octene copolymer rubber, and ethylene-propylene-dienecopolymer rubber; ethylene-vinyl acetate copolymer rubber; andethylene-glycidyl methacrylate copolymer.

Among the above-mentioned olefin elastomers, preferable areethylene-α-olefin copolymer rubbers such as ethylene-propylene copolymerrubber, ethylene-butene copolymer rubber, ethylene-octene copolymerrubber, and ethylene-propylene-diene copolymer rubber. Among them,ethylene-octene copolymer rubber and ethylene-propylene-diene copolymerrubber using a metallocene catalyst are more preferable.

The vinyl polymer segment which constitutes the graft copolymer of thepresent invention and is formed from a vinyl monomer having an acid isan addition polymer in which one or more molecules of a vinyl monomerhaving an acid are polymerized.

As the vinyl monomer having an acid, vinyl monomers having carboxylicacids, vinyl monomers having carboxylic acid anhydrides, vinyl monomershaving sulfonic acids, and vinyl monomers having phosphoric acids arepreferable in terms of adhesive properties to and compatibility withpolar materials, and further scratch resistance.

Specific examples of vinyl monomers having carboxylic acids includemethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonicacid, and methyltetrahydrophthalic acid.

Specific examples of vinyl monomers having carboxylic acid anhydridesinclude maleic anhydride, itaconic anhydride, methyltetrahydrophthalicanhydride, and endomethylenetetrahydrophthalic anhydride.

Specific examples of vinyl monomers having sulfonic acids includemethacryl sulfonate, vinyl sulfonate, and p-styrene sulfonate.

Specific examples of vinyl monomers having phosphoric acids includeethylene glycol methacrylate phosphate and polyethylene glycolmethacrylate phosphate.

Among these vinyl monomers having acids, use of vinyl monomers havingcarboxylic acids or carboxylic acid anhydrides is preferable for thepresent invention in terms of the acid content in the graft copolymer.In particular, use of acrylic acid and maleic anhydride is mostpreferable.

Further, vinyl monomers having these acids may be used either alone orin combination of two or more kinds thereof.

The amount of vinyl polymer segment which is formed from the vinylmonomer having an acid and contained in the graft copolymer of thepresent invention can be calculated, for example, from a peak height ofinfrared absorption spectrum of the acid obtained by FT-IR.

The amount of the vinyl polymer segment formed from the vinyl monomerhaving an acid is preferably in the range of 0.1 to 30% by weight in thegraft copolymer, more preferably 1 to 20% by weight. When the amountthereof is less than 0.1% by weight, the performances of the graftcopolymer such as adhesive properties and scratch resistance arerelatively low, and it is unfavorable. Further, greater than 30% byweight of the acid is unfavorable, because the properties of polyolefinresin cannot be obtained.

In terms of molecular weight, the graft copolymer of the presentinvention preferably has a number average molecular weight obtained bystyrene conversion of 1,000 to 10,000,000, and more preferably 2,000 to5,000,000 obtained by high temperature GPC (Column: Toso TSKgelGMHHR-H(20)HTx2, column temperature: 135° C., detector temperature: 135°C., sample temperature: 135° C., pump: 60° C., injection volume: 100 μl,solvent: orthodichlorobenzene, analytical time: 30 minute).

When the number average molecular weight is less than 1,000, themechanical properties are relatively low, and it is unfavorable.Further, when the number average molecular weight is greater than10,000,000, the reforming effects become insufficient, and it isunfavorable.

The graft copolymer of the present invention may contain byproductcompounds generated during the production of the graft copolymer, thatis to say, non-grafted polyolefin resins, vinyl polymer formed from thevinyl monomer having an acid, a decomposition product or a gel ofpolyolefin resin.

A graft copolymer composition containing the graft copolymer of thepresent invention can contain two or more kinds of graft copolymers.

Above all, more preferable is a mixture of: a graft copolymer composedof a polypropylene resin and a vinyl polymer segment formed from a vinylmonomer having an acid; and a graft copolymer composed of an olefinelastomer segment and a vinyl polymer segment formed from a vinylmonomer having an acid. This is because the combination of them exhibitsproperties intermediate between resin and rubber as the combinationattracts attention in a new field called as polyolefin thermoplasticelastomer.

For the purpose of controlling the acid amount, a polyolefin resin canbe newly added to the graft copolymer composition of the presentinvention.

Further, the addition of polyolefin resin can uniformly disperse thegraft copolymer in the graft copolymer composition and enhance anapplication property, an adhesive property to dissimilar materials,scratch resistance, and wear resistance.

As the polyolefin resin to be added at this time, the above-mentionedpolyolefin resin and a mixture thereof can be used.

The mixing ratio of the graft copolymer and polyolefin resin (graftcopolymer/polyolefin resin) can be arbitrarily changed in the range of99.5/0.5 to 0.5/99.5.

Particularly, from an economical view point, the mixing ratio ispreferably 50/50 to 0.5/99.5

When the weight ratio of the graft copolymer contained in a graftcopolymer composition is less than 0.5%, the scratch resistance and wearresistance of the graft copolymer composition are relatively low and itis not undesirable. On the other hand, when the weight ratio of thepolyolefin resin contained in the graft copolymer composition is lessthan 0.5%, the above-mentioned reforming effect by addition ofpolyolefin is hard to be obtained.

For the purpose of enhancing scratch resistance or wear resistance, itis preferable that the graft copolymer composition of the presentinvention is partially crosslinked.

As crosslinking methods, there can be either of the following methods ora combination thereof: a method for intramolecular and intermolecularcrosslinking by ionic bond using a metal salt or an organic amine by useof the acid of the graft copolymer composition; and a method forintramolecular and intermolecular crosslinking by covalent bond using anorganic peroxide or sulfur by use of the polyolefin resin segment of thegraft copolymer composition.

Examples of metal salt to be used for crosslinking method by ionic bondinclude sodium salts, calcium salts, magnesium salts, zinc salts,lithium salts, and aluminum salts. In addition, examples of the organicamines include n-hexylamine, hexamethylenediamine, and1,3-bis(aminomethyl)cyclohexane.

Among them, from a viewpoint of moldability and scratch resistance andwear resistance, metal salts are preferable, and magnesium salts, zincsalts, and aluminum salts are more preferable.

Further, as methods for neutralizing the acid of the graft copolymercomposition by a metal salt or an organic amine, any of the followingmethods can be used: a method for neutralizing a vinyl monomer having anacid by a metal salt or an organic amine before producing the graftcopolymer composition; a method for neutralizing an acid of the graftcopolymer composition by a metal salt or an organic amine after graftreaction; and a method for neutralizing by a metal salt or an organicamine after polyolefin resin is further added into the graft copolymercomposition.

The addition of metal salt or organic amine has an upper limit ofequimolar amount based on the amount of the acid of the graft copolymercomposition.

Specific examples of organic peroxides to be used for the method forcrosslinking by covalent bond include dicumyl peroxide,α,α′-bis(t-butylperoxy)diisopropylbenzene,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane,2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, t-butylperoxybenzoate,and benzoyl peroxide.

Among them, from a viewpoint of enhancing scratch resistance, wearresistance, and tensile property of the graft copolymer composition,dicumyl peroxide, α,α′-bis(t-butylperoxy)diisopropylbenzene,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 are preferable.

Specific examples of sulfur to be used for the method for crosslinkingby covalent bond include organic sulfur donors such astetramethylthiuramdisulfide and 4,4-dithiobis(morpholine) in addition tosimple substance sulfur such as insoluble sulfur and colloidal sulfur.

Among them, from the aspect of versatility and economical efficiency,simple substance sulfur such as insoluble sulfur and colloidal sulfur ismore desirable.

Here, the amount of crosslinking agent to be added is not greater than10 parts by weight and more preferably not greater than 5 parts byweight, based on 100 parts by weight of graft copolymer composition.Addition of more than 10 parts by weight of crosslinking agent lowersthe moldability of the graft copolymer composition, and it is notpreferable.

For the purpose of enhancing, especially, scratch resistance, wearresistance and tensile property, a crosslinking co-agent can be furtheradded to the graft copolymer composition of the present invention whencrosslinking is conducted by a crosslinking agent such as organicperoxides and sulfur.

As the crosslinking co-agent, usable are: a dimer or trimer of a vinylmonomer to be used in crosslinking by an organic peroxide, or acrosslinking accelerator used in crosslinking by sulfur; an activator;and a retarder.

Specific examples of the dimer or trimer of a vinyl monomer includedivinylbenzene (ortho-, meta-, and para-),ethyleneglycoldi(meth)acrylate, trimethylolpropanetri(meth)acrylate, anddiallyl phthalate.

Among them, divinylbenzene (not limited to any of ortho-, meta-, andpara-), ethyleneglycoldi(meth)acrylate, andtrimethylolpropanetri(meth)acrylate are preferable.

These may be used either alone or by mixing two or more kinds thereof.

Specific examples of the crosslinking accelerator include sulfenamide,benzothiazole, guanidine, and dithiocarbamic acid.

Specific examples of the activator include metal oxides such as zincoxide and magnesium oxide, aliphatic acids such as stearic acid.

Specific examples of the retarder include acids such as phthalicanhydride and salicylic acid, and nitroso compounds such as N-nitrosodiphenylamine.

These can be properly used according to required properties, and alsoeither alone or by mixing two or more kinds thereof.

Here, the amount of crosslinking co-agent to be added is not greaterthan 10 parts by weight and more preferably not greater than 5 parts byweight, based on 100 parts by weight of graft copolymer or a compositionthereof. Addition of more than 10 parts by weight of crosslinking agentlowers the moldability of the graft copolymer composition.

For the purpose of enhancing, especially, scratch resistance and wearresistance, a lubricant can be added to the graft copolymer compositionof the present invention.

Specific examples of the lubricant include: hydrocarbons such asparaffin wax and polyethylene wax; aliphatics such as stearic acid;higher alcohols such as stearyl alcohol; amides such as oleic amide,ethylenebis (oleamide); esters such as monoglyceride stearate; metalsoaps such as zinc stearate; silicones such as silicone oil; andalkylene glycols such as polyethylene glycol and polyethylene glycolmonomethylether. In particular, from a viewpoint of enhancing scratchresistance and wear resistance of the graft copolymer composition,hydrocarbons, amides, silicones, and alkylene glycols are preferable.

The amount of lubricant to be added is preferably not less than 0.1 andnot greater than 30 parts by weight based on 100 parts by weight ofgraft copolymer composition. When the amount thereof exceeds 30 parts byweight, the properties of polyolefin cannot be obtained. When the amountis less than 0.1 parts by weight, improvement effects of scratchresistance and wear resistance cannot be observed.

Moreover, as long as it does not deviated from the objects of thepresent invention, the graft copolymer composition of the presentinvention, if necessary, can contain: flame retardants includingphosphorous compounds and halogen-containing compounds such ashalogenated styrene; fortified fillers such as carbon fiber, mica andtalc; antioxidants such as phenolic ones, thioether ones and phosphorusones; plasticizers such as phthalic esters, adipic esters, phosphateesters, polyesters, and mineral oils; stabilizers; dispersants; foamingagents; ultraviolet ray inhibitors; and coloring agents.

Next, a method for producing the graft copolymer composition of thepresent invention will be described.

The graft copolymer composition of the present invention can be producedby reacting a vinyl monomer having an acid with polyolefin resin havingβ-substituted propenyl group as a pendant.

Here, as polyolefin resin having β-substituted propenyl group as apendant, usable is, for example, a product which is produced as aresidual chain by removing tertiary radical from a skeleton of anaddition-fragmentation chain transfer agent after theaddition-fragmentation chain transfer agent is reacted with a polymerradical of a polyolefin molecule generated in polyolefin resin.

Specific examples of β-substituted propenyl group include a2-phenyl-1-propenyl group, a 2-cyano-1-propenyl group, and a2-acetoxy-1-propenyl group.

Among them, from a viewpoint of preventing a main chain from being cut,2-phenyl-1-propenyl group is preferable.

Moreover, the addition-fragmentation chain transfer agent is notparticularly limited and all of known chain transfer agents havingproperties of addition cleavage type can be used. Among them, anaddition-fragmentation chain transfer agent represented by the chemicalformula (B) is preferable.

In the formula (B), R¹ and R² represent a phenyl group, a cyano group oran alkyl ester group (in —COOR^(m), R^(m) represents an alkyl grouphaving 1 to 4 carbon atoms), and R³ represents a hydrogen group or amethyl group.

Specific examples of the addition-fragmentation chain transfer agentinclude: styrene chain transfer agents such as2,4-diphenyl-4-methyl-1-pentene, 2-phenyl-4-cyano-4-methyl-1-pentene,and α-(methyl 2-methyl-propanoate)styrene; acrylonitrile chain transferagents such as 2,4-dicyano-1-pentene and ax-(methyl2-methylpropanoate)acrylonitrile; methyl acrylate chain transfer agentssuch as α-(2-phenyl-propyl)methyl acrylate and α-(2-methylpropanoic acidmethyl)methyl acrylate.

Among them, from a viewpoint of the introduction ratio of β-substitutedpropenyl group, a styrene addition-fragmentation chain transfer agenthaving R¹ of a phenyl group in the chemical formula (B) is preferable.In particular, from an economical point of view,2,4-diphenyl-4-methyl-1-pentene and 2-phenyl-4-cyano-4-methyl-1-penteneare more preferable.

The addition amount of addition-fragmentation chain transfer agent usedherein is preferably 0.2 to 40 parts by weight and more preferably 0.5to 20 parts by weight based on 100 parts by weight of polyolefin resin.

When the addition amount of addition-fragmentation chain transfer agentis less than 0.2 parts by weight, the graft copolymer compositionunfavorably has relatively low adhesive property to a vinyl polymersegment formed from a vinyl monomer having an acid and declined scratchresistance. On the other hand, when the addition amount thereof exceeds40 parts by weight, the properties of polyolefin resin cannot beobtained and it is not preferable.

In producing polyolefin having β-substituted propenyl group as apendant, a radical polymerization initiator or a radical scavenger canbe used in combination.

Here, as the radical polymerization initiator or radical scavenger,compounds described below can be used in copolymerizing polyolefin resinhaving β-substituted propenyl group as a pendant and a vinyl monomerhaving an acid.

The graft copolymer of the present invention can be obtained by reactingpolyolefin resin having β-substituted propenyl group as a pendant with avinyl monomer having an acid. A method for reacting them with each otheris not particularly limited and any method can be used as long aspolyolefin resin having β-substituted propenyl group as a pendant and anacid-containing monomer, etc. are fully mixed and reacted with eachother.

The reaction can be conducted, for example, by ultraviolet irradiation,but a method for reacting by heating and mixing is most preferable froma viewpoint of reaction efficiency.

In reacting polyolefin resin having β-substituted propenyl group as apendant with a vinyl monomer having an acid by heating, it is preferableto conduct the reaction in the presence of a radical polymerizationinitiator. Here, the radical polymerization initiator usable means allof known compounds that generate radical.

Specific examples of the radical polymerization initiator includedicumyl peroxide, α,α′-bis(t-butylperoxy)diisopropylbenzene,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane,2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, benzoyl peroxide,ammonium persulfate, potassium persulfate, sodium persulfate,2,2-azobisisobutyronitril, and 2,2-azobisisovaleronitrile.

Among them, from a viewpoint of enhancing the introduction ratio of acidin the graft copolymer composition, dicumyl peroxide,α,α′-bis(t-butylperoxy)diisopropylbenzene,2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 are preferable.

Here, the addition amount of radical polymerization initiator is notgreater than 10 parts by weight and more preferably 0.1 to 5 parts byweight based on 100 parts by weight of polyolefin resin havingβ-substituted propenyl group as a pendant. When the addition amountthereof exceeds 10 parts by weight, the polyolefin resin havingβ-substituted propenyl group as a pendant is easily disintegrated orcrosslinked and thus it is not preferable.

For the purpose of preventing gelation or resin deterioration, a radicalscavenger is preferably used in heating and mixing after adding a vinylmonomer having an acid to polyolefin resin having β-substituted propenylgroup as a pendant.

Specific examples of the radical scavenger include: primary antioxidantssuch as 2,6-di-t-butyl-4-methylphenol andtetrakis-[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane;secondary antioxidants such as di-lauryl thio-di-propionate andtris-nonylphenyl-phosphite; and nitroxide compounds. These are usedeither alone or in combination of two or more kinds thereof.

Among them, a nitroxide compound represented by the chemical formula (C)is preferable since gelation is efficiently prevented in obtaining thegraft copolymer composition.

In the formula (C), R⁴, R⁵, R⁸, and R⁹ represent a straight chain orbranched alkyl group, an aromatic-substituted alkyl group, an aromaticgroup, or an alkyl-substituted aromatic group. Further, R⁶and R⁷may beindependent or coupled with each other to form a cyclic structure, andeach represents a straight chain or branched alkyl group, a hydroxyalkylgroup, an alkoxyalkyl group, an alkylcarbonyloxy group, a cyano group, acarboxyl group, an alkyloxycarbonyl group, a benzoyloxy group, an alkoxygroup, an amino group, a hydroxyl group, a nitro group, a sulfonicgroup, a phosphate group, or an aromatic group.

Specific examples of the nitroxide compound represented by the formula(C) include di-t-butylnitroxide,N-t-butyl-1-diethylphosphono-2,2-dimethylpropylnitroxide,2,2,5,5-tetramethylpyrrolidinyl-1-oxy,2,2,6,6-tetramethylpiperidinyl-1-oxy, and2,2,6,6-tetramethyl-5-hydroxypiperidinyl-1.

Among the above-mentioned nitroxide compounds,2,2,6,6-tetramethylpiperidinyl-1-oxy and2,2,6,6-tetramethyl-5-hydroxypiperidinyl-1-oxy are particularlypreferable.

Here, the addition amount of nitroxide compound is not greater than 10parts by weight and more preferably 0.1 to 5 parts by weight based on100 parts by weight of polyolefin resin having β-substituted propenylgroup as a pendant. When the addition amount thereof exceeds 10 parts byweight, the acid introduction ratio in the graft copolymer compositionunfavorably decreases.

In reacting polyolefin resin having β-substituted propenyl group as apendant with a vinyl monomer having an acid in the present invention, amethod of heating in combination with a radical polymerization initiatorand a radical scavenger is more preferable combination from a standpointof the reaction efficiency and the prevention of gelation ordeterioration of resin.

In heating and mixing after adding a vinyl monomer having an acid topolyolefin resin having β-substituted propenyl group as a pendant,copolymerization can be conducted in combined use of a vinyl monomer toimprove the acid introduction ratio in the graft copolymer and tolengthen a chain of polymer of the acid-containing vinyl monomer in thegraft copolymer.

In reacting polyolefin resin having β-substituted propenyl group as apendant with a vinyl monomer having an acid, any of the followingmethods can be employed for production: for example, a melting/kneadingmethod wherein the reaction is conducted using an extruder, a Banburymixer, a kneader, a kneader-ruder or the like; a solution reactionmethod wherein the reaction is conducted in a state of uniform solutionusing a solvent with dissolution ability; and a solid-state reactionmethod wherein the reaction is conducted in a state of powder, a sheetor the like.

Among them, a melting/kneading method is more preferable from astandpoint of handiness and economical efficiency.

In addition, the reaction temperature is preferably not less than 20° C.

Here, more preferable temperature is 30 to 400° C. in the case ofaddition of a radical polymerization initiator, and 100 to 400° C. inthe case of no addition thereof.

When the radical polymerization initiator is added at a temperature ofless than 30° C., the reaction rate tends to be too low. Similarly, whenthe reaction is conducted at a temperature of less than 100° C. withoutaddition of the racial polymerization initiator, the reaction rate tendsto be too low. On the other hand, when the reaction temperature exceeds400° C. in either case, the polymerization proceeds too rapidly and thecontrol of the reaction tends to be difficult.

A molded product can be obtained by molding the graft copolymercomposition of the present invention into a designated shape. As amethod of molding the graft copolymer composition, molding can beconducted by a processing machine generally used for thermoplasticresin, and exemplary methods include calendar molding, an extrusionmolding, foam molding, injection molding, vacuum molding, and blowmolding. Extrusion molding is preferable from a standpoint ofmoldability and high gloss appearance. Foam molding is preferable from astandpoint of lower specific gravity. Injection molding is preferablefrom a standpoint fluidity and high gloss appearance.

Articles which can be obtained by molding the graft copolymercomposition of the present invention include: sheet-like molded productssuch as films and sheets; bulk-like molded products such as plates,rods, and tubes. In the case of molding a sheet-like molded product,T-die extrusion molding or calendar molding are more desirable from astand point of moldability and appearance. In the case of molding abulk-like molded product, extrusion molding, blow molding, foam molding,and injection molding are more preferable from a standpoint ofmoldability and appearance. Specific examples of molded productsinclude: sheet-like molded products such as seat surface material forvehicles, seat surface material for chairs, shrink film for foods;bulk-like molded products such as Automotive moldings for vehicles,weather strips, mud guards, and grips for sticks. Especially, seatsurface material for vehicles, automotive moldings, molded products forweather strip are more preferable from a standpoint of adhesiveproperty, scratch resistance, and surface gloss of a molded product.Examples of seat surface material includes surface material forinstrument panel, surface material for trim, surface material for bodyside trim, surface material for luggage side trim, surface material forroof trim, surface material for sun visor, and surface material forpillar trim. Examples of automotive moldings include front windowmolding, rear window molding, drip molding, door waist molding, rearpillar molding, lock pillar automotive molding side guide molding, beltmolding, and roof molding. Examples of weather strip include body side,door seal, side window, trunk rid, tail gate, rear quarter, windowshield, glass run, and rear partition. These molded products includeproducts produced by gluing one or more kinds of materials by heatwelding or further laminating urethane elastomer on the molded product,multi layered molded films having gravure printing of urethane coating,primers, coating main agents, and molded products covered with hardcoating.

The obtained molded products can be collected after use and can bereused as material for molding, and thus it is excellent in recycling.

According to the present invention, the following advantages can beobtained.

The graft copolymer has a structure in which a vinyl polymer segmentformed from a vinyl monomer having an acid is suspended in a molecularchain of polyolefin resin segment via a β-substituted propylene group.Therefore, the graft copolymer having less disintegration orcrosslinking of polyolefin resin segment and higher introduction ratioof vinyl monomer having an acid can be obtained, compared with a graftcopolymer having a structure in which an acid is suspended withoutβ-substituted propylene group, and the obtained graft copolymer and acomposition thereof are excellent in adhesive property and scratchresistance.

Further, adhesive property and scratch resistance of the graft copolymercomposition can be improved by partial crosslinking.

Furthermore, adhesive property and scratch resistance of the graftcopolymer composition can be much improved by allowing it to contain alubricant.

According to the production methods of the graft copolymer, it ispossible to obtain a graft copolymer composition whose molecular weighthas not changed while graft reaction and to which much acid has beengrafted.

Next, the present invention will be described in detail by referring toExamples and Comparative Examples, but the present invention is notlimited thereto. In these examples, “part” and “%” mean “parts byweight” and “% by weight” unless otherwise stated.

Further, each measurement items of each example were obtained inaccordance with the following methods.

(1) Melt Flow Rate

Melt flow rate (abbreviated as MFR in tables) was measured in accordancewith JIS K 7210 (temperature: 190° C., load: 2.16 kg).

(2) Gel Fraction

1 g of polyolefin resin having α-substituted propenyl group as a pendantor graft copolymer, and 100 g of a mixture of 180 g of cyclohexane and20 g of dimethylformamide were charged in a Soxhlet extractor, and thenextraction was conducted for 24 hours at a temperature of the boilingpoint of the solvent.

Then, based on the weight (g) of extracted residue obtained by removingcyclohexane and dimethylformamide from cylindrical filter paper and theweight (g) of a sample before extraction, a gel fraction {gel fraction(%)=[(weight of extracted residue (g))/(sample weight (g) beforeextraction)]×100} was calculated.

(3) Amount of Suspension of β-Substituted Propenyl Group in PolyolefinResin having a β-Substituted Propenyl Group as a Pendant

1 g of polyolefin resin having a β-substituted propenyl group as apendant was added to 200 g cyclohexane and dissolved at 70° C.Thereafter the resultant solution was dropped in 600 g of acetone forreprecipitation.

The precipitate was filtrated and dried, and the resultant product wasdissolved in heavy cyclohexane. Then, the amount of suspendedβ-substituted propenyl group (%, abbreviated as suspension amount intables) was determined in accordance with the following method using¹H-NMR.

In ¹H-NMR measurement, for example, β-substituted propenyl group (when asubstituent is a phenyl group) to be detected are attributable asfollows.

-   2.8 ppm; methylene proton-   4.7 and 5.1 ppm; proton of a methylene double bond-   7.0 to 7.2 ppm; benzene ring proton

Therefore, based on the ratio of the integrated area (A) of proton ofmethylene double bond to the integrated area (B) of methylene proton(1.3 ppm) derived from ethylene or propylene of polyolefin component ormethyl proton (0.8 to 0.9 ppm), and molar fraction (C) of ethylene orpropylene in polyolefin resin component, the number of moles (Md=A×C/B)of methylene double bond in one mole of polyolefin resin component canbe calculated.

The product (Md×Mp) of the number of moles (Md) of methylene double bondin one mole of polyolefin resin component and the molecular weight (Mp)of β-substituted propenyl group is divided by the molar-molecular weight(Mw) of polyolefin resin, (Md×Mp/Mw), and thereby the suspension amountof β-substituted propenyl group can be calculated (suspension amount ofβ-substituted propenyl group (%)=Md×Mp/Mw={A×C×Mp/(B×Mw))×100).

(4) Amount of Suspension of β-Substituted Propylene in Graft Copolymer

1 g of graft copolymer was added to 200 g of a mixture of 180 g ofcyclohexane and 20 g of dimethylformamide, and dissolved at 70° C.Thereafter the resultant solution was dropped in 600 g of acetone forreprecipitation.

The precipitate was filtrated and dried, and the resultant product wasdissolved in heavy cyclohexane. Then, the amount of suspendedβ-substituted propylene group (%, abbreviated as suspension amount intables) was determined in accordance with the following method using¹H-NMR.

In ¹H-NMR measurement, for example, β-substituted propenyl group (when asubstituent is a phenyl group) to be detected are attributable asfollows.

-   2.8 ppm; methylene proton-   3.7 ppm; methine proton-   7.0 to 7.2 ppm; benzene ring proton

Therefore, based on the ratio of the integrated area (a) of methineproton to the integrated area (b) methylene proton (1.3 ppm) derivedfrom ethylene or propylene of polyolefin component or methyl proton (0.8to 0.9 ppm), and molar fraction (c) of ethylene or propylene inpolyolefin resin component, the number of moles (Mm=a×c/b) of methineproton in one mole of polyolefin resin component can be calculated.

The product (Mm×Mq) of the number of moles (Mm) of methine proton in onemole of polyolefin resin component and the molecular weight (Mq) ofβ-substituted propylene group is divided by the mol-molecular weight(Mw) of polyolefin resin (Mm×Mq/Mw), and thereby the suspension amountof β-substituted propylene group can be calculated (suspension amount ofβ-substituted propylene group (%)=Mm×Mq/Mw={a×c×Mq/(B×Mw)}×100).

(5) Acid Content and Reaction Rate

1 g of graft copolymer was added to 200 g of a mixture of 180 g ofcyclohexane and 20 g of dimethylformamide, and the resultant mixture wasstirred for 2 hours at 70° C. for dissolving graft copolymer.Thereafter, the resultant solution was dropped in 600 g of acetone forreprecipitation.

The precipitate was filtrated and dried and the resultant product washeat-pressed (230° C., 5 MPa), thereby forming a film with a thicknessof 0.2 mm.

With infrared absorption spectrum, the absorbance of peaks attributableto carboxylic acid, anhydrous carboxylic acid, sulfuric acid,andphosphoric acid (carboxylic acid: 1710 to 1730 cm⁻¹, anhydrouscarboxylic acid: 1760 to 1780 cm⁻¹, sulfuric acid: 1010 to 1080 cm⁻¹,phosphoric acid: 1180 to 1240 cm⁻¹) was measured, and the content (%) ofintroduced acid or acid anhydride was calculated by a calibration curvemethod.

Then, the graft reaction rate was calculated (graft reaction rate(%)={content (%) of acid or acid anhydride introduced to graftcopolymer/content (%) of feed acid or acid anhydride}×100).

Here, the content (%) of feed acid or acid anhydride means the content(%) of vinyl monomer containing acid or acid anhydride based on thetotal amount of the vinyl monomer containing feed acid or acid anhydrideand polyolefin resin containing β propenyl group in reacting polyolefinresin containing β propenyl group with vinyl monomer containing acid oracid anhydride.

(6) Hardness

The hardness of graft copolymer composition was measured in conformityto JIS K 6253.

(7) Adhesive Property

The graft copolymer composition was molded by heat-compression for 2minutes at 220° C. and 10 MPa, thereby molding a molded product having 2mm of thickness and a square plate shape with 80 mm on a side. Themolded product was sandwiched by two aluminum plates which have beendefatted and have 0.1 mm of thickness and mirror finished surface, andmolded by heat-compression for 2 minutes at 200° C. and 10 MPa, therebyforming a molded aluminum product with 0.85 mm of resin thickness.

The resultant product was cut into pieces with 25 mm of width, andconditioned for 24 hours under the conditions of 23° C. and 50%humidity. Thereafter, T-peel strength was measured with a test distanceof 60 mm at a pulling rate of 50 mm/min. using an autograph (AGS-H 500Nmanufactured by Shimadzu Corporation).

(8) Scratch Resistance

A molded product (square plate with 2 mm of thickness and 120 mm on aside) of the graft copolymer was molded and the scratch resistance wasevaluated according to three methods shown below.

Scratch Resistance Performance

Using a scratch tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), atest piece was scratched by a cutter with an arbitrary load appliedthereto, and a minimum load that caused a scar on the test piece wasmeasured.

Erichsen Resistance Performance

Using a scratch hardness tester (Model 318 manufactured by Erichsen), anarbitrary load was applied to a ball with 0.5 mmφ and scratching wasconducted, and a minimum load that caused a scar on a test piece wasmeasured.

Wear Resistance Performance

Using a Frictional wear instrument (manufactured by Yasuda Co.), 1000 gof load was placed on a face of 10 mmφ, and 100 times of reciprocalabrasion was performed with Cotton cloth (No.3). Thereafter, a surfaceof a test piece was visually observed and evaluated in accordance withthe following evaluation standard.

-   -   4: when a flaw width is 0.0 to 0.5 mm (0 to 5%)    -   3: when a flaw width is 0.6 to 2.5 mm (6 to 50%)    -   2: when a flaw width is 2.6 to 9.5 mm (51 to 95%)    -   1: when a flaw width is 9.6 to 10.0 mm (96 to 100%)        (9) Tensile Test

A product of graft copolymer (a square plate with 2 mm of thickness, 120mm on a side) was molded, and subjected to tensile test in conformity toJIS K 6251.

Hereinafter, abridged notations in Examples, Comparative Examples andtables represent the following substances.

-   PP: block polypropylene (trade name: SunAllomer PB370A manufactured    by SunAllomer Ltd.)-   PE: polyethylene (tradename: Sumikasen G401manufactured by Sumitomo    Chemical Co.)-   m-EOR: ethylene-octane copolymer rubber (trade name: Engage 8180    manufactured by DuPont Dow Elastomers L.L.C.)-   m-EPDM: ethylene-propylene-diene copolymer rubber synthesized by    metallocene catalyst (trade name: Nordel IP4725P manufactured by    DuPont Dow Elastomers L.L.C.)-   MAN modified PP: maleic acid modified polypropylene (tradename:    OREVAC CA100 containing 1% of maleic acid, manufactured by ATOFINA)-   MAN modified EPDM: maleic acid modified ethylene-propylene-diene    copolymer rubber (trade name: Royaltuf 498 containing 1% of maleic    acid, manufactured by Uniroyal)-   MSD: 2,4-diphenyl-4-methyl-1-pentene (trade name: Nofmer MSD    manufactured by NOF CORPORATION)-   H-25B: 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (trade name:    Perhexa 25B manufactured by NOF CORPORATION)-   H-TEMPO: 2,2,6,6-tetramethyl-5-hydroxypiperidinyl-1-oxy    (manufactured by Hulls)-   MAN: maleic anhydride (manufactured by NOF CORPORATION)-   AA: acrylic acid (Wako Pure chemical Industries, Ltd.)-   ZAA: zinc acetate (Wako Pure chemical Industries, Ltd.)-   DVB: divinylbenzene (Wako Pure chemical Industries, Ltd.)-   MEG: polyethylene glycol monomethylether (trade name: Uniox 550    manufactured by NOF CORPORATION)

REFERENCE EXAMPLE 1 Production of β Propenyl Group Pendant PP

100 parts of PP (density: 0.9, melt flow rate (JIS K 7210: 230° C., 2.16kg of load) 1.3 g/10 min.), 5 parts of MSD, 1 part of H-25B, and 1 partof H-TEMPO were mixed for 5 minutes by a mixing/stirring machine, andthen the resultant mixture was melt and kneaded at 220° C. in anatmosphere of nitrogen with a biaxial extruder with an internal diameterof 30 mm and an L/D of 30, thereby producing polypropylene resin having2-phenyl-1-propenyl group as a pendant.

Next, the produced polyolefin resin was analyzed by ¹H-NMR (AV 400 modelmanufactured by Bruker Japan Co., Ltd.)

-   0.8 to 0.9 ppm; methyl proton (B) 3H (495)-   1.3 ppm; methylene proton (B) 2H (0)-   2.8 ppm; methylene proton 2H (1.02)-   4.7 ppm, 5.1 ppm; proton of methylene double bond (A) 2H (1)-   7.0 to 7.2 ppm; proton of benzene ring 5H (2.54)    The numerical values in brackets represent relative strength of    peaks.

Based on the ratio of the integrated area (A) of proton of methylenedouble bond to the integrated area (B: since polyolefin resin herein ispolypropylene, methyl proton is used) of methyl proton (0.8 to 0.9 ppm)derived from propylene of polyolefin component, and the molar ratio (C:herein the value thereof is 1) of propylene of polyolefin resincomponent, the number of moles (Mb=C×(A/2)/(B/3)) of unsaturated doublebond in one mole of polyolefin resin component is calculated as follows.Mb=1×(1/2)/(495/3)=0.00303

The product (Md×Mp) of the number of moles (Mb) of unsaturated doublebond in one mole of polyolefin resin component and the molecular weight(Mp) of β-substituted propenyl group is divided by the mol-molecularweight (Mw) of polyolefin resin (herein polypropylene), (Md×Mp/Mw), andthereby the suspension amount of β-substituted propenyl group can becalculated (suspension amount (%) of β-substituted propenylgroup=Md×Mp/Mw=A×C×Mp/(B×Mw)×100).

Herein:suspension amount (%) of β-substituted propenylgroup=0.00303×117/40×100=1.8

Using this PE having 2-phenyl-1-propenyl group as a pendant, the meltflow rate and gel fraction were measured. The results are shown inTable 1. TABLE 1 Reference examples 1 2 3 4 Blended Polyolefin resin pp100 components PE 100 (parts) m-EOR 100 m-EPDM 100 Addition MSD 5 5 5 5cleavage type chain transfer agent Radical H-25B 1 1 1 1 polymerizationinitiator Radical H-TEMPO 1 1 1 1 scavenger Melting/kneading temperature(° C.) 220 220 180 180 Properties of β-substituted MFR 12 2.4 0.9 0.5propenyl group containing (g/10 min.) resin Gel fraction 0 6 1 2 (%)Introduction 0.9 1.8 1.9 2.0 ratio (%)(Reference Example 2: production of PE having β-propenyl group as apendant)

PE having 2-phenyl-1-propenyl group as a pendant was obtained in thesame manner as Reference Example 1 except that polyolefin resin waschanged to PE (density: 0.9, melt flow rate (JIS K 7210 (190° C., 2.16kg of load): 4.0 g/10 min.), and various evaluations were conducted inthe same manner. The results are shown in Table 1.

REFERENCE EXAMPLE 3 Production of m-EOR having β-Propenyl Group as aPendant

m-EOR having 2-phenyl-1-propenyl group as a pendant was obtained in thesame manner as Reference Example 1 except that polyolefin resin waschanged to m-EOR (melt flow rate (JIS K 7210: 230° C., 2.16 kg of load):1 g/10 min.) and the melting/kneading temperature was changed to 180°C., and various evaluations were conducted in the same manner. Theresults are shown in Table 1.

REFERENCE EXAMPLE 4 Production of m-EPDM having β-Propenyl Group as aPendant

m-EPDM having 2-phenyl-1-propenyl group as a pendant was obtained in thesame manner as Reference Example 1 except that m-EPDM (melt flow rate(JIS K 7210: 230° C., 2.16 kg of load): 0.5 g/10 min.) was used insteadof polyolefin resin and the melting/kneading temperature was changed to180° C., and the various evaluations were conducted in the same manner.The results are shown in Table 1.

EXAMPLE 1 Production and Performance of Graft Copolymer Composition inwhich an Acid is Suspended

100 parts of PP having β-propenyl group as a pendant synthesized inReference Example 1, 5 parts of MAN, and 1 part of H-25B were mixed for5 minutes by a mixing/stirring machine, and then the resultant mixturewas melt and kneaded at 220° C. in a nitrogen atmosphere by a biaxialextruder having 30 mm of internal diameter and L/D of 30, therebyproducing PP having polymaleic anhydride grafted.

Next, the produced graft copolymer was analyzed by ¹H-NMR (AV 400 modelmanufactured by Bruker Japan Co., Ltd.).

-   0.8 to 0.9 ppm; methyl proton (b) 3H (557.8)-   1.3 ppm; methylene proton (b) 2H (0)-   2.8 ppm; methylene proton 2H (1.02)-   3.7 ppm; methine proton (b) 2H (1)-   7.0 to 7.2 ppm; proton of benzene ring 5H (2.54)    The numerical values in brackets represent relative strength of    peaks.

Based on the ratio of the integrated area (a) of methine proton to theintegrated area (b: since polyolefin resin herein is polypropylene,methyl proton was used) of methyl proton (0.8 to 0.9 ppm) derived frompropylene of polyolefin component, and the mole ratio (c: herein thevalue thereof is 1) of propylene of polyolefin resin component, thenumber of moles (Mm=c×(a/2)/(b/3) of methine in one mole of polyolefinresin component is calculated as follows.Mm=1×(1/2)/(557.8/3)=0.00269

The product (Mm×Mq) of the number of moles (Mm) of methine in one moleof polyolefin resin component and the molecular weight (Mq) ofβ-substituted propylene group is divided by the mol-molecular weight(Mw) of polyolefin (herein polypropylene) (Mm×Mq/Mw), and thereby thesuspension amount of β-substituted propylene group can be calculated(suspension amount (%) of β-substituted propylenegroup=Mm×Mq/Mw={a×c×Mq/(b×Mw)}×100).

Herein,suspension amount (%) of β-substituted propylenegroup=0.00269×117/40×100=0.8Using this composition, the melt flow rate, gel fraction, acid amountand reaction rate were measured.

In addition, this graft copolymer composition was molded byheat-compression for 2 minutes at 220° C. and 10 MPa, thereby molding amolded product having 2 mm of thickness and a square plate shape with 80mm on a side. Then, the obtained product was evaluated in terms of theadhesive property, scratch resistance, and tensile property, and theresults are shown in Table 2. TABLE 2 Examples Comparative 1 2 3 Example1 Blended Polyolefin resin Reference 100 100 100 — components example 1(parts) PP — — — 100 Vinyl monomer MAN 5 0.1 — 5 containing acid AA — —5 — Radical polymerization H-25B 1 1 1 1 initiator Properties of graftcopolymer MFR (g/10 min.) 27 20 22 46 composition containing acid Gelfraction (%) 0 4 0 0 Content of 0.8 0.4 0.8 — β-substituted propylene(%) Acid content (%) 3.20 0.14 2.60 0.42 Reaction rate (%) 64 70 52 8Performances of Hardness Shore D (JISA) 71 70 72 71 graft copolymerAdhesive Peeling strength 13 5 12 5 composition property (N/mm)containing acid Flaw Scratch resistance 1.5 0.5 1.7 0.2 resistance (N)Erichsen 9.0 8.8 9.0 8.0 resistance (N) Wear resistance 4 4 4 4 (point)Tensile Maximum stress 35 32 34 28 property (MPa) Elongation (%) 600 660680 580

EXAMPLE 2

A graft copolymer composed of PP having polymaleic acid grafted wasobtained in the same manner as Example 1 except that the amount of MANwas changed from 5 parts to 0.1 parts, and the various evaluations wereconducted in the same manner. The results are shown in Table 2

EXAMPLE 3

A graft copolymer composed of PP having polyacrylic acid grafted wasobtained in the same manner as Example 1 except that 5 parts of AA wasused instead of 5 parts of MAN, and the various evaluations wereconducted in the same manner. The results are shown in Table 2.

EXAMPLE 4

PE composition having polymaleic anhydride grafted was obtained in thesame manner as Example 1 except that 100 parts of PE having β-propenylgroup as a pendant was used instead of 100 parts of PP having β-propenylgroup as a pendant, and the various evaluations were conducted in thesame manner. The results are shown in Table 3. TABLE 3 Examples 4 5 6 7Blended β-substituted Reference Example 2 100 — — — components propenylgroup- Reference Example 3 — 100 — — (parts) containing resin ReferenceExample 4 — —  100  100 Vinyl monomer MAN  5  5   5   5 containing acidRadical H-25B  1  1   1 — polymerization initiator Radical scavengerH-TEMPO — — —   1 Performance of graft copolymer MFR (g/10 min.)  1.8 2.5   0.4   1 containing acid Gel fraction (%)  6  2   3   1 Content of 1.6  1.7   1.8   1.7 β-substituted propylene (%) Acid content (%)  2.70 3.20   3.50   3.10 Reaction rate (%)  54  64  67  77 Performances ofHardness Shore D (JISA)  (55)  (55)   (55)   (55) graft copolymerAdhesive property Peeling strength  12  18  20  18 composition (N/mm)containing acid Flaw resistance Scratch resistance  1.7  1.3   1.8   1.8(N) Erichsen resistance  2.5  1.2   1.2   1.5 (N) Wear resistance  4  3  3   2 (point) Tensile property Maximum stress (MPa)  17  1.6   6.7  7.0 Elongation (%) 420 770 1100 1200

EXAMPLE 5

M-EOR composition having polymaleic anhydride grafted was obtained inthe same manner as Example 1 except that 100 parts of m-EOR havingβ-propenyl group as a pendant, which was produced in Reference Example3, were used instead of 100 parts of PP having β-propenyl group as apendant in obtaining PP composition having polymaleic anhydride grafted,and the various evaluations were conducted in the same manner. Theresults are shown in Table 3.

EXAMPLE 6

m-EPDM composition having polymaleic anhydride grafted was obtained inthe same manner as Example 1 except that 100 parts of m-EPDM havingβ-propenyl group as a pendant, which was produced in Reference Example4, were used instead of 100 parts of PP having β-propenyl group as apendant in obtaining PP composition having polymaleic anhydride grafted,and the various evaluations were conducted in the same manner. Theresults are shown in Table 3.

EXAMPLE 7

m-EPDM composition having polymaleic anhydride grafted was obtained inthe same manner as Example 6 except that 1 part of H-TEMPO was added inobtaining m-EPDM composition having polymaleic anhydride grafted, andthe various evaluations were conducted in the same manner. The resultsare shown in Table 3.

EXAMPLE 8 Production of Graft Copolymer Composition

30 parts of graft copolymer composition obtained in Example 1 and 70parts of graft copolymer composition obtained in Example 7 were melt andkneaded for 10 minutes in a 75 cc Banbury mixer (BH-75 manufactured byToyo Seiki Seisaku-sho, Ltd.) at 100 rpm, thereby producing a graftcopolymer composition.

Further, this graft copolymer composition was molded by heat-compressionfor 2 minutes at 220° C. and 10 MPa, thereby molding a molded producthaving 2 mm of thickness and a square plate shape with 80 mm on a side.Thereafter, the obtained product was evaluated in terms of adhesiveproperty, scratch resistance, and tensile property, and the results areshown in Table 4. TABLE 4 Examples Comparative 8 9 10 11 Example 2Blended Graft copolymer Example 1 (PP)  30 — 30  30 — componentscomposition Example 7  70  70 — — — (parts) (m-EPDM) MAN modified PP — —— — 30 MAN modified — — — — — EPDM Polyolefin PP —  30 70 — 70 resinm-EPDM — — —  70 — Performances MFR MFR (g/10 min.)  0.4  1.2 35  1.4 30of graft Hardness Shore D (JISA) copolymer Adhesive Peeling strength (87)  (86) 70  (87) 70 composition property (N/mm) containing Flawscratch  3.1  2.4 1.0  2.0 0.3 acid resistance resistance (N) Erichsen 1.5  1.4 9.0  1.0 9.0 resistance (N) Wear resistance  4  4 4  4 4(point) Tensile Maximum stress  9.5  9.0 23.3  8.8 31.0 property (MPa)Elongation (%) 630 630 550 670 500

EXAMPLE 9

A graft copolymer composition was obtained in the same manner as Example8 except that 30 parts of PP were used instead of 30 parts of graftcopolymer composition obtained in Example 1, and the obtained productwas molded. Thereafter, the same evaluations on the molded product wereconducted. The results are shown in Table 4.

EXAMPLE 10

A graft copolymer composition was obtained in the same manner as Example8 except that 70 parts of PP were used instead of 70 parts of graftcopolymer composition obtained in Example 7, and the obtained productwas molded. Then, the same evaluations on the molded product wereconducted. The results are shown in Table 4.

EXAMPLE 11

A graft copolymer composition was obtained in the same manner as Example8 except that 70 parts of m-EPDM were used instead of 70 parts of graftcopolymer composition obtained in Example 7, and the obtained productwas molded. Then, the same evaluations on the molded product wereconducted. The results are shown in Table 4.

EXAMPLE 12

A graft copolymer composition was obtained in the same manner as Example8 except that 30 parts of PP and 30 parts of graft copolymer compositionobtained in Example 7 and 40 parts of m-EPDM were used instead of 30parts of graft copolymer composition obtained in Example 1, and 70 partsof graft copolymer composition of Example 7, and the obtained productwas molded. Then, the same evaluations on the molded product wereconducted. The results are shown in Table 5. TABLE 5 ExamplesComparative 12 13 14 15 Example 3 Blended Graft copolymer Example 1 (PP)— — — — — components composition Example 7 (m-EPDM)  30  30  30  30 —(parts) MAN modified PP — — — — — MAN modified EPDM — — — —  30Polyolefin resin PP  30  30  30  30  30 m-EPDM  40  40  40  40  40 Metalion 20% ZAA aqueous —  9  9  9  9 solution Crosslinking H-25B — —  0.5 0.5  0.5 agent Crosslinking DVB — —  0.3  0.3  0.3 aid Lubricant MEG —— —  5  5 Performances of MFR MFR (g/10 min.)  1.8  1.5  1.3  1.7  2.3graft copolymer Hardness Shore D (JISA)  (88)  (88)  (88)  (88)  (87)composition Adhesive peeling strength  11  10  10  9  2 containing acidproperty (N/mm) Flaw scratch  1.4  1.5  1.7  1.9  0.3 resistanceresistance (N) Erichsen  1.2  1.5  1.9  2.7  1.0 resistance (N) wearresistance  4  4  4  4  4 (point) Tensile maximum stress (MPa)  8.8  9.2 9.6  9.5  9.0 property elongation (%) 690 640 590 570 570

EXAMPLE 13

A graft copolymer composition was obtained by further adding 9 parts of20% ZAA aqueous solution to the graft copolymer composition obtained inExample 12, and the obtained product was molded. Then, the sameevaluations on the molded product were conducted. The results are shownin Table 5.

EXAMPLE 14

A graft copolymer composition was obtained by further adding 0.5 partsof H-25B and 0.3 parts of DVB to the graft copolymer compositionobtained in Example 12, and the obtained product was molded. Then, thesame evaluations on the molded product were conducted. The results areshown in Table 5.

EXAMPLE 15

A graft copolymer composition was obtained by further adding 5 parts ofMEG to the graft copolymer composition obtained in Example 14, and theobtained product was molded. Then, the same evaluations on the moldedproduct were conducted. The results are shown in Table 5.

COMPARATIVE EXAMPLE 1

100 parts of PP (density: 0.9, melt flow rate (JIS K 7210: 230° C., 2.16kg of load) 1.3 g/10 min.), 5 parts of MAN, and 0.5 parts of H-25B weremixed for 5 minutes by mixing/stirring machine, and then melt andkneaded by a biaxial extruder having 30 mm of internal diameter and L/Dof 30 (in a nitrogen atmosphere at 220° C.), thereby obtaining PPcomposition having polymaleic anhydride directly grafted. The variousevaluations were conducted. The results are shown in Table 2.

COMPARATIVE EXAMPLE 2

A graft copolymer composition was obtained in the same manner as Example10 except that 30 parts of MAN modified PP were used instead of 30 partsof graft copolymer obtained in Example 1, and the obtained product wasmolded. Then, the same evaluations on the molded product were conducted.The results are shown in Table 4.

COMPARATIVE EXAMPLE 3

A graft copolymer composition was obtained in the same manner as Example15 except that 30 parts of MAN modified EPDM were used instead of 30parts of graft copolymer composition obtained in Example 7, and theobtained composition was molded. Then, the same evaluations on themolded product were conducted. The results are shown in Table 5.

According to the comparison between Example 1 and Comparative Example 1(Table 2), PP of the present invention having polymaleic anhydridegrafted has higher content of maleic anhydride, compared with the casewherein conventional PP was used as material in the reaction forobtaining a graft copolymer composition by grafting polymaleicanhydride. Further, it has been revealed that PP of the presentinvention is excellent in adhesive property and scratch resistance.

In addition, according to the comparison between Example 2 andComparative Example 1 (Table 2), PP of the present invention havingpolymaleic anhydride grafted exhibits equal or better adhesive propertyand scratch resistance of graft copolymer composition, despite loweracid introduction amount, compared with the case wherein conventional PPwas used as material. Therefore, it is clear that the performances ofthe graft copolymer composition of the present invention have beenimproved because the composition has a structure in which polymaleicacid is grafted via β-substituted propylene group, rather than directly,to polyolefin resin segment.

Further, according to the comparison between Example 10 and ComparativeExample 2 (Table 4), it is obvious that PP of the present inventionhaving polymaleic anhydride group grafted is excellent in adhesiveproperty and scratch resistance for PP composition, compared withcommercially available maleic anhydride modified PP.

Moreover, according to the comparison between Example 15 and ComparativeExample 3 (Table 5), when EPDM of the present invention having maleicanhydride grafted is used as a modifier, compared with commerciallyavailable maleic anhydride modified EPDM described in Japanese PatentPublication No. 2-51455, it has become obvious that the obtained resincomposition is excellent in adhesive property and scratch resistance.

INDUSTRIAL APPLICABILITY

The graft copolymer of the present invention has a structure in which avinyl polymer segment formed from a vinyl monomer having an acid issuspended in a molecular chain of polyolefin resin segment via aβ-substituted propylene group. Therefore, in comparison with a graftcopolymer having a structure in which an acid is suspended without theintermediate of β-substituted propylene group, the graft copolymer ofthe present invention has less disintegration or crosslinking ofpolyolefin resin segment, and enable the obtainment of a graft copolymerhaving higher introduction ratio of vinyl monomer having an acid.Consequently, the graft copolymer and a composition thereof areexcellent in adhesive property and scratch resistance.

Further, according to a method for producing the graft copolymer of thepresent invention, the change of molecular weight during graft reactionis small and it is possible to obtain a graft copolymer compositionhaving larger amount of grafted acid.

From the graft copolymer composition of the present invention, variousmolded products can be obtained, for example: sheet-like molded productssuch as sheets and films; bulk-like molded products such as plates,rods, and tubes. These molded products can be collected after use andreused as material for molding, and thus they are excellent inrecycling.

1. A graft copolymer having a structure in which a vinyl polymer segmentformed from a vinyl monomer having an acid is suspended in a molecularchain of polyolefin resin segment via a β-substituted propylene group:2. The graft copolymer according to claim 1, wherein the β-substitutedpropylene group is a group represented by the formula (A):

wherein R¹ represents a phenyl group, cyano group or —COORm (Rmrepresents an alkyl group having 1 to 4 carbon atoms)
 3. The graftcopolymer according to claim 1, wherein the polyolefin resin segment isa polypropylene resin segment.
 4. The graft copolymer according to claim1, wherein the polyolefin resin segment is an olefin elastomer segment.5. The graft copolymer according to claim 1, wherein the content of thevinyl polymer segment is 0.1 to 30% by weight.
 6. A graft copolymercomposition containing the graft copolymer according to claim
 1. 7. Thegraft copolymer composition according to claim 6, wherein partialcrosslinking is present.
 8. The graft copolymer composition according toclaim 6, wherein the composition contains further a lubricant.
 9. Amolded product obtainable by molding the graft copolymer compositionaccording to claim
 6. 10. A method for producing a graft copolymer byreacting a vinyl monomer having an acid with polyolefin resin having aβ-substituted propenyl group as a pendant.
 11. A method for producing agraft copolymer by reacting a vinyl monomer having an acid withpolyolefin resin having a β-substituted propenyl group as a pendant byheating and mixing at a temperature of not less than 30° C. and not morethan 400° C.
 12. The method for producing a graft copolymer according toclaim 10, wherein the polyolefin resin having a β-substituted propenylgroup as a pendant is produced by reacting an addition-fragmentationchain transfer agent with polyolefin resin.
 13. The graft copolymeraccording to claim 2, wherein the polyolefin resin segment is apolypropylene resin segment.
 14. The graft copolymer according to claim2, wherein the polyolefin resin segment is an olefin elastomer segment.15. The graft copolymer according to claim 2, wherein the content of thevinyl polymer segment is 0.1 to 30% by weight.
 16. A graft copolymercomposition containing the graft copolymer according to claim
 2. 17. Thegraft copolymer composition according to claim 16, wherein partialcrosslinking is present.
 18. The graft copolymer composition accordingto claim 16, wherein the composition contains further a lubricant.
 19. Amolded product obtainable by molding the graft copolymer compositionaccording to claim
 16. 20. The method for producing a graft copolymeraccording to claim 11, wherein the polyolefin resin having aβ-substituted propenyl group as a pendant is produced by reacting anaddition-fragmentation chain transfer agent with polyolefin resin.